


My Treasure

by MindscapeWish



Category: Gravity Falls
Genre: Adult Dipper Pines, Angst with a Happy Ending, Bottom Bill Cipher, Established Relationship, Fingering, Fluff and Smut, Kinktober, M/M, Pirate AU, Pirate Dipper Pines, Siren Bill Cipher, Top Dipper Pines, bills kinda a brat, lots of hickies, siren au, slight Breeding Kink, tiny hints to vore kink if you squint, vaginal terminology
Language: English
Status: Completed
Published: 2020-10-02
Updated: 2020-10-02
Packaged: 2021-03-08 02:47:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,886
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26768242
Author URL: https://archiveofourown.org/users/MindscapeWish/pseuds/MindscapeWish
Summary: Bill left the Pines family's ship two, very long months ago on a search, and Dipper's worried sick. When he finally returns home, they have a special night all to themselves to catch up.Or:The oneshot where Dipper is very angsty, then Bill comes back, and suddenly they're fucking in a glass tank.
Relationships: Bill Cipher/Dipper Pines
Comments: 1
Kudos: 91





	My Treasure

**Author's Note:**

  * For [Dorky_Dipper](https://archiveofourown.org/users/Dorky_Dipper/gifts).



Dipper looked over the ship’s railings down into the white, churning water as they sailed across. He sighed, brows crinkled together in worry and a frown on his lips. Mabel always told him that if he stayed in that position for too long that it’d be permanent, but he couldn’t help it.

Two months. It’d been two months since he’d last seen his boyfriend Bill and he became more anxious by the day. Dipper didn’t know where he was, what he was doing, or if he was even alive.

The day that Bill had left the side of the ship, they’d docked at a rocky shore and he’d given Dipper a dizzying, breath-taking kiss that left Dipper’s lips swollen red. “I’ll be back before you know it, Pinetree!” he had winked, pulling Dipper’s pine tree bandana down over the brunette’s eyes playfully. Without another word, Bill leapt off of the rocks and into the water.

Dipper definitely knew it. The fear of finding Bill’s dead body floating on the surface of the water rose in his chest, tearing his lungs and tightening his throat. He couldn’t bear waiting for the inevitable.

Before Dipper could work himself into more of a panic, he was startled by Mabel jumping up behind him and grabbing his shoulder. “What’s wrong, bro-bro?”

Dipper shrieked in a  _ very _ manly way and clung to the railing, fearing he’d tip overboard. “What the heck, Mabel?!”

Mabel gave a loud cackle and slapped Dipper’s back twice. “Hah, got ‘im! I said what’s wrong?”

Dipper gave her a dirty look for scaring him, but ultimately sank back down against the railing with a sigh. “Today marks two months.”

“Two months of wh--” Mabel stopped herself, eyes slowly widening in realization.  _ Since Bill left. _ She knew that he and Dipper had been way closer than expected even for a romantic relationship, so she couldn’t even imagine the unease Dipper was feeling right now. “ _ Oh. _ ”

Dipper nodded grimly. “Oh is right. I--I don’t know where he is, if he’s okay, if he found what he was looking for or was hurt, or--” He swallowed hard, barely registering Mabel’s pitying look from the corner of his eye. “I don’t know if he’s even alive, Mabel…”

“I’m sure he’s fine,” Mabel replied softly, wrapping her arm around Dipper’s shoulders. “You know how easily distracted he is! One shiny thing and he’s gone looking for it. He probably just found a lot of adventures-- like  _ we _ should be doing, looking for that treasure and all!”

“You’re right.” Mabel was usually right with things like these, especially with bringing up Bill’s nature. He was incredibly focused on only a few rare things in Dipper’s time of knowing him, and the rest of the time his attention span could shift from one thing to another in a split second’s time.

“Of course I am, bro-bro!” Mabel crowed. “Alpha twin! Alpha twin!” She yanked him away from the railing of the ship, earning a squeak, and pulled him along to the kitchen. “Now c’mon! I heard that Soos is gonna fit an entire cantaloupe into his mouth!”

Dipper gawked. “What?! How?! Where did we even get one of those?”

“I don’t have to tell you everything.” Mabel grinned back at him mischievously.

From there, Mabel went around trying to keep Dipper’s mind off of everything. She cheered on Soos sticking the cantaloupe in his mouth, mop fought Grunkle Stan, watched Wendy fight a ravenous seagull trying to steal her food, and pulled Dipper along to whatever else she could find. When it came down to chores around the ship, she dumped a bunch of work onto Dipper so he could maybe be distracted.

That only worked as long as she was constantly flocking around him even throughout all his annoyed remarks to keep his attention. Dipper being left alone with his thoughts was not a good thing.   
  
It was night time when Dipper finally caught a break. The sun slipped below the horizon, its remnants splashing the lower sky with light yellow. The pale color was quickly chased out by pitch dark of dark blues, cloudy greys and void. Twinkling, shimmering white stars and a big bright moon replaced it.

Dipper found these nights to be most calming. There was something about the total still of the night, the pattern of the steady rocking of the ship that he had memorized, and the cold breeze that swept through. Being alone up on the main deck where he could see everything, if anything at all with his hurricane lamp, was an alienating type of calm.

Nights like these, Dipper made peace with being alone in the universe. There was no fear that came ebbing in upon the thoughts of the unknown or the inevitable, but an easing and peaceful release. Dipper’s existence was a speck of dust in all the known cosmos-- he didn’t mean much in the grand scheme of things, but at least he meant something to his family.

Dipper tightened his bandana around his head to keep it from getting swept off in the breeze and leaned against the deck railing. His eyes drooped and limbs ached from the gruelling day his sister plagued him with, but he couldn’t go to sleep. Not with Bill out there.

If he rested now, Bill might slip through his fingers further.

The wind went down the back of Dipper’s loose shirt and he shivered, pulling his lips closer into his body.

“Where are you?” he whispered. His words swept away with the churning of the water and roaring of the ocean, but he hoped that they could reach their destination maybe one last time.

Dipper was close to giving up hope. Maybe Bill had gotten sick of him, or maybe he was truly gone and holding on like this was putting Dipper into much more misery than he should. 

A strong part of him held tight to the hope like it was a life line, stubborn and uncontrolled, demanding to keep searching. Bill would come back to him. He was the most annoying, conniving, silver tongued asshole siren Dipper had ever met, but he was also resourceful, intelligent, just as stubborn, and strong-willed. Bill would come back to him. All Dipper needed to do was wait.

A little whisper in the back of his head, though, told him that Bill’s precarious and volatile nature had turned on Dipper and led him away. Maybe he got into a fight, or perhaps in the wrong place at the wrong time snooping and is floating in a barrel for food, or fished/poached,  _ something. _

Dipper’s heart sank lower the more he thought about it. Suddenly the cold felt much more sharp, sinking deep into his bones and isolating him. This was stupid. He should just go back to his cabin and go to sleep. All of this was probably just being overtired from all of Mabel copping out on chores. When the morning came, he’d be fine.

Dipper took one last look at the pitch black dark of the ocean below him and sighed, turning.

A flash of light from the surface of the waves caught the corner of his eye.

Dipper whipped his head back around, eyes widening to saucers. It wasn’t just any flash of light. It was  _ Bill’s. _ The eerie, luminescent yellow-blue glow of his scales never felt so relieving, so like  _ home. _

His heart stopped in his chest, an accidental high pitched squeak accompanying his gasp. Bill was home. He was home after so long, returned to him after the inevitable, after  _ anything _ could have happened.

“Bill!” he shrieked, practically bending himself over the rail. Dipper held out the lamp, hoping to everything above Bill would see his lantern and stop. It almost felt like if Dipper didn’t catch his attention now, Bill would pass by and never notice him.

Several long moments passed with only the sound of the whipping wind and the roaring of the ocean. Dipper strained his ears, holding onto the possibility of hearing something like it was a life line.

“-- _ netree! _ ”

Tears came to Dipper’s eyes, an overwhelming wave of relief flushing over his body. Bill was here for sure, alive and okay and  _ home. _

“Bill!” he cried, waving frantically off the side of the boat. Dipper watched the glowing scales stop moving once they reached the area of the ship where the sailboats could be reeled down.

“--inetree! Let me up!”

Dipper dashed towards the pulley and stuck the lamp handle into his mouth so his hands were free. Hurriedly, he tugged at the knots in the ropes that kept everything secure with shaking, cold-burning fingers. They slipped several times but he kept on in a rush.

Bill was here, Bill was  _ home _ , and no amount of reassurances or repetitions of that single phrase was going to make Dipper believe it any more. If he didn’t get the boat down quick enough, he feared Bill would be swept away for another several months.

Finally the knots loosened and the sailboat lurched with the sudden slack in the ropes. Dipper swore he felt his teeth creak as he bit down harder on the metal while he worked to lower the boat. This damn thing better not come off its ties and crash down into the water-- that’d happen once already, and although it wasn’t a lot, it was a pain in the ass to get that fucker back.

Dipper felt the sailboat on the ropes move and sway once Bill got on after it hit the water.

“Reel me up, Dippy!”

Dipper quickly began yanking the ropes up, the added weight of Bill and his heavy tail making the job even more of a struggle. He swore it was heavier than he remembered though. Huh, whatever. He was a strong tough pirate though, he could do this!

Soon Bill’s head poked over the top of the railing and Dipper knotted up the ropes to keep everything in place.

That familiar sharp, shit-eating grin met his gaze. God, Dipper had missed him so much. He couldn’t help but start to tear up, setting the lamp down and yanking Bill into a hug.

“Where were you, you asshole?!”

Bill laughed and hugged Dipper in return, soaking his clothes. He patted his back, clearly not understanding the situation totally. “I was out getting treasure, what did you think I was doing?”

“I thought you were dead! I thought I’d find you floating or beached on the shore or something!” Dipper sniffled, shoving his face into Bill’s chest. The tears that fell mixed with the salt water on Bill’s body.

BIll scoffed, though it was softer than his earlier responses. Dipper crying was never a good thing, but this was over something dumb. “It’s only been a few days, Pinetree.”

Dipper froze and ripped himself out from Bill’s embrace. “A few days?!” He shoved the lamp close enough to their faces that they felt the licking heat off of the flame. “It’s been two fucking months, Bill!”

Dipper almost found Bill’s shocked, paling expression funny.  _ Almost _ .

“Two months? No no, that can’t be right. I just left!” Bill’s brow furrowed together, frowning and trying to make sense of it all. Right? Only a few… dozen… moons passed. He sighed heavily. “Shit.”

“ _ Yeah. _ ” Dipper’s wobbling bottom lip slowly evened out and he sniffled, wiping his wet face on his sleeves. “Whatever. You’re home now. You have no idea how much I’ve missed you.”

Bill wiped away Dipper’s tears with his thumbs and kissed the birthmark on his forehead. “I’ve missed you too, Pinetree. I didn’t waste one day so that I could come back and see you. In fact, look at all this bullshit I found!”   
  
A giant chest sat near the ending fin of Bill’s tail, dark and water-logged wood rotting and the lock coming off its place within the framework.

Huh. That explained the extra weight.

Dipper’s mind wiped his worries away temporarily, gaping at the chest. “Is that a  _ treasure _ chest?!” Bill really hadn’t been lying! There  _ was _ treasure!

Bill leaned his chin on his palm, smirking. His finned ears twitched, giving away how happy he was to see Dipper excited even though he looked smug. “Why don’t cha’ give it a look’sie and tell me?”

Dipper’s eyes positively lit up and scrambled over to that side of the sailboat, lamp thrust forward to see. The wooden lid was heavy with water, so it took both hands to open. He dropped the lid back against the sailboat and gaped.

Inside was  _ pure gold. _ There were mounds of gold coins, necklaces, bracelets, brooches, more than enough silver copies, rubies,  _ everything. _ Dipper had no idea this much treasure ever existed in the world.

“Oh my god!”

“You likey?” Bill flicked his tail teasingly, looking much too similar to a cat that caught the canary. He  _ knew _ he did. Dipper was always so expressive that it showed clear as day on his face.

“Do you know what this means?!” Dipper squeaked, head snapping back up to Bill.

“That I’m the best boyfriend in the world and you should totally take me to bed?”

Dipper flushed deeply and smacked Bill’s tail where he could reach. “No, you horny bastard. We’re rich! Soos can finally send enough home to fix his house and feed his kids, and-and-- Wendy won’t have to leave the ship to work anymore, and I can get those mythology books I’ve been wanting for years!”

Bill hummed and nodded disinterestedly, distracted. Instead of listening to it all, he was checking Dipper out, eyes roaming his body up and down.

Dipper shivered under his gaze. It was near predatory, like Bill wanted to devour him whole. It wasn’t… a  _ protested _ idea, however they both knew who the top here was. Dipper briefly recalled the many times Bill writhed below him, nails tearing up his back and crying out for more.

“Ugh, what’s wrong with you?” Dipper mumbled. He leaned down and hauled the  _ very _ heavy treasure chest out of the sailboat. From there he stumbled his way towards a room on the top deck for storage so that he could come back to this in the morning.

“Couldn’t you tell? I’m horny, kid, haven’t had you in  _ ages. _ Aren’t you gonna pick me up?” Bill called.

Dipper hip bumped the door open and thumped the chest down onto the ground. He made sure the door was locked behind him so that it wasn’t potentially stolen if something happened. “Hold your horses, you’re not the main priority,” he joked.

Bill’s jaw dropped. “Oh, how dare you! I just got home and offering a good time, and you throw it away! Wow, ungrateful little shit.” He crossed his arms over his chest and looked away, grumbling.

Dipper rolled his eyes and went over to scoop Bill up. Bill couldn’t exactly move himself everywhere easily, so it was their routine for him to be carried down to their shared cabin in one of the lower decks.

Dipper handed Bill the lantern and hauled him up to his chest, grunting, “Don’t be such a drama queen.” Slimy scales pressed against his arms and drenched him even more, but he couldn’t care at this point. He headed back to the stairs towards the back of the deck.

Bill wrapped his arm around Dipper’s neck, the other outstretching to light their way back. “Excuse you, that’s my occupation.”

“I thought being an annoying, mean boyfriend with no consideration to anyone’s interests but your own was your occupation.”

“Youch, Pinetree, that hurts.”

“You know I’m joking.” For the first time in two months, Dipper finally got to turn his head and kiss Bill. Bill’s lips were cold and salty from the ocean, but a little time and smooching and he’d be good as human.

Bill hummed, eyes slipping shut as he pressed back into the kiss. No matter what his heart always fluttered, but time away had made it worse. He swore Dipper could feel his heartbeat race from how he was pressed against him.

Dipper couldn’t feel it, but he was wondering the same thing too. Kissing him after so long was like coming back home. It settled the buzzing in his body and his worries, placing a balm over all the fractures in his soul.

He had to pull away to make sure he was stepping down one at a time instead of two like the last time he’d carried Bill down. Their lips separated with a little pop and they both caught their air in little pants.

Bill wasn’t satisfied with just that one kiss. He was definitely demanding more once they got into their cabin, but for now, Dipper’s neck was right there all ripe for the taking. He chuckled low to himself and pulled the collar of Dipper’s shirt to the side. Bill’s lips latched onto a particular spot on that soft, creamy neck that always drove his boy up the wall.

Dipper’s eyes widened a bit and he flushed a bright red, shrugging up his shoulder. “B-Bill-- what are you--?”

Even with Dipper trying to block him off, Bill stayed in his position. He rubbed his tongue against a patch of skin, suckling to make a beautiful purple bruise. “Mm, no’hin.”

“Stop, you’re gonna make a mark.” If Mabel saw the next morning, Dipper’s ass was toast. Contrary to his words, though, something low in his belly tingled and wanted more.

“Exactly what I want to do, Pinetree.” Bill grazed his sharp teeth against the sensitive bruise and felt a shiver run through Dipper’s body. He grinned up at him mischievously. “Oh, you really liked that, huh, big boy?”

Dipper did his best to give Bill a dirty look, but it wasn’t like it would deter him. More so it would just encourage him. His resolve faltered and he looked away, hoping some of his flustered-ness wouldn’t get to Bill. “Leave it for the bedroom, Bill.”

“We’re  _ going _ to the bedroom. That counts,” Bill defended. No one was around anyways. What was the big deal?

“No, it doesn’t.” Dipper really just didn’t want to let Bill make a habit of feeling him up when they were out where anyone could see them. He already made crass remarks and slapped his ass in public whenever Dipper passed by, so this was an important line to keep in the sand.

“Oh, you’re no fun.”   
  
Dipper could hear the pout in Bill’s voice, but didn’t care. Bill was a drama queen and got a lot of things he wanted anyways. Putting his foot down once wouldn’t kill him.

Dipper quietly made his way to the other side of the ship where his and Bill’s cabin was. Luckily it was away from the others’ cabins more or less, so they had more privacy for…  _ things. _

Bill had missed this place. It had quickly become home for him once he and Dipper got to know each other. He’d memorized every book in Dipper’s trunk, every scratch on the bedpost, knot in the wood, and trinket on Dipper’s workspace.

The room opened up into something on the smaller side but cozy. There was a bed with nicer, beige and grey sheets in the middle of the room against a wall. At the foot of the bed laid a big trunk, full of most of Dipper’s belongings such as his clothes and prized books. A big tank full of water, big enough for Bill to comfortably stretch out and move as he pleased, was on the right. Across from that on the other side of Dipper’s bed was a large, open-table space full of quills and ink pots, paper, trinkets, journals, and various items used for map-coursing. Ink stained the wood and more often than not, Dipper’s hands.

Dipper set the lamp down on the trunk and hauled Bill up higher than before to lower him into his tank. Bill let go of his neck and put his arms down into the water against the bottom to brace himself. Dipper then released him.

“Oh~!” Bill giggled and moved about in a wiggly fashion, tail flipping in the water. “You changed out the water too, just for me! I feel all special now.”

“I don’t want you dying, so, yeah.” Dipper rolled his eyes to Bill’s astoundment, though he did find the sight cute. He hadn’t seen such a happy Bill in so long, so he clutched this memory to heart and never let it go.

“Oh, don’t be like that,” Bill huffed. He lifted his top half and leaned over the tank, head resting on his forearms on the edge so he could see Dipper. “I know you loooove me.”

Dipper set the lamp down and took a match so he could light a few candles around the room. It’d be easier to see this way. “I know you know I love you.”

“Then don’t act all tough and distant.” Bill would have splashed some water at Dipper with his fin, but that would put out the candles. He’d rather see Dipper with those lit, especially for the romantic-ish atmosphere. “Get in, I want to see you.”

“You can see me right now.” Dipper tapped the tank like he was trying to bother a fish and grinned.

“I don’t mean  _ that _ kind of seeing.” Bill smirked over at him. It’d been a long while since he’d gotten Dipper’s touch and taste. He wanted to memorize it all again.

Dipper raised his brow and leaned close, Bill just a smidge higher up than him. Their faces were so close that their lips were just inches apart, feeling each other’s breath. “Then what type of seeing do you want?” he purred.

Bill swallowed, cheeks just barely flushing. He hoped the minimal flickering light hid it. “The type of seeing where you’re on top of me,” he murmured in reply, leaning forward. They were an inch away now, so close that the teasing hurt. Butterflies erupted in both of their stomachs, breaths hitching. “And you’re fingering me open until I beg you to finally put it in me.”

Dipper’s stomach dropped, heat filling his belly. Just a little dirty talk and his pants were already tightening. He bit his lip and smirked, looking into Bill’s eyes. There was nothing except reverent need and a genuine question in his siren’s stare. “Is that all you could think about tonight? Me railing you against the side of your tank?”

Bill nodded slowly. The slit a few inches below his hips ached for Dipper’s fingers, or better yet, something a little  _ thicker. _ “And tying my hands together with your bandana… Stuffing my mouth with your tongue to shut me up.” He leaned closer, now barely half an inch away. His voice dropped into a whisper, dripping in sensual need. “I thought about you at night, y’know… Sometimes touched myself in the dark of caves, imagining it was you.”

Dipper’s breath hitched, eyes glancing down to Bill’s lips. They were beautiful, tanned like the rest of his skin with soft pinks, plump and soft. God, he couldn’t resist him. He snapped to undoing his clothing, belt coming off in clatters and shirt much too complex with its buttons for his patience.

“Tell me what you did to yourself, sweetheart,” Dipper purred.

Bill eyed Dipper’s body as each article of clothing stripped off to reveal sun-tanned skin that made him drool. “I laid down on my back and… I started at the top. I pretended like my hand was yours, pinching and tweaking my nipples…” His slit throbbed, just like it had when he’d fantasize about Dipper on top of him in those late nights. There was something unbelievably hot about telling somebody all the personal, naughty little things you’ve done.

Dipper listened intently, prick hardening with every image that Bill brought into his mind. His pants dropped and his shirt slipped off onto the floor. He swore that he couldn’t strip fast enough. He quickly yanked his socks and bandana off, underwear joining the rest of the clothes on the floor.

Bill nearly choked, eyes locked onto Dipper’s cock. It was halfway hard, growing and straightening before his very eyes, and he’d  _ never _ hungered so badly for it in his fucking life. Dipper didn’t have the longest dick, but made up for it in  _ girth. _ God, the siren was left an absolute mess by the time Dipper was done with him. Dipper reached spots he never thought he’d feel, slit stretched wide and cock pressing against his walls.

He whimpered and slipped his hand down into the water to pet at his slit. Patience, patience, patience was a virtue, but he didn’t seem to have any.

“I--” He swallowed, watching Dipper smirk at his reaction and start making his way into the tank. “I would tease myself. Stroke my pussy until I couldn’t take it anymore, suck my fingers…”

Dipper shivered, cock twitching. Bill always called his slit his pussy since the first time he found out it made Dipper twitch so deliciously. Dipper couldn’t help it-- there was something about it that felt so sinfully dirty that he loved. But more importantly, Bill had teased himself alone thinking about Dipper.

Dipper stepped up on a stool and climbed into Bill’s tank, the water cold on his already hot skin. He swore Bill made him so warm that they could single handedly make the water boil.

Bill dropped back into the tank, stretching out his tail all for Dipper to see. He continued stroking his slit but with extra fervor, the parting in his tail opening a little with each press down.

“Tell me the rest,” Dipper ordered him. How could Bill disobey? All of his bravado went down the drain whenever Dipper gave him that hungry look.

“I fucked myself over and over again for hours some nights,” Bill whispered. They were so close, Dipper kneeling over and his cock so deliciously close to his pussy that it quivered. “Losing myself and crying out your name until I lost my voice, three fingers inside me at once, thrusting in and out like how you fuck me mercilessly…”

“Mm…” Dipper eyed Bill’s body up and down, hunger in his eyes. Bill was the predator here, yet he felt like Dipper would eat him right up. God, that was hot. “I knew you were a needy cockslut, but I didn’t know you were to that extent.”

Bill shuddered involuntarily, unable to reply. Dipper was usually more than gentle with him, but these rare nights where Dipper became nasty were real treats. Bill was either suspended for hours and edged, humiliated and degraded (a well known kink of his) or everything happened so fast and rough that BIll got whiplash and enough orgasms to last him a month. 

Dipper looked down to the canvas that was Bill’s body. So much to do with such an eager siren beneath him... how  _ beautiful. _ He had a feeling that Bill would come undone under his touch lickity split with how long they’d been apart.

He placed his cold hands on Bill’s warm waist and rubbed upwards in one long stroke, feeling the hot, soft skin below his touch. Bill’s nipples eagerly hardened with barely any touch, bringing Dipper’s attention to them.

“It’s been a while since you’ve had these sucked, huh?” Dipper smirked, grasping the pinkish nubs and pinching them. Bill let out a broken moan and arched up into Dipper’s hands.

“Give it to me, baby,” he groaned, “I can’t wait any longer. I’m throbbing for you.”

Dipper noted how desperate and amped up Bill sounded, but pocketed it for later. He instead leaned down, one hand slipping beneath Bill’s back and lifting his torso up from the water. Dipper wrapped his lips eagerly around one nipple, the other hand toying with the other.

“O--Oh fucking hell--” Bill bit his lip, trying to keep back moans. His nipples were sensitive and Dipper  _ always _ targeted them first, damn it! That sinful tongue of his swirled around and flicked it, teeth lightly grazing and making Bill mewl pathetically.

Dipper smirked up at him and took a hard pull at the nipple. Bill was easy to undo like this-- just a little rub and he fell apart in Dipper’s hands. Honestly, it was quite adorable.

Bill, usually, had such a sense of confidence grounded in the weirdest BS that it was easier arguing with a brick wall than with him. He did whatever he wanted,  _ said _ what he wanted, and had plenty of silver tongue to get out of consequences about the previous two.

However here, in this tank, Dipper had the upper hand. Dipper was the one breaking him down into shambles, pathetic moans and begs to give him more. The duality between both sides of Bill had been jarring when they’d first gotten intimate, though Dipper had easily come to love (or be annoyed of, in some cases) both.

The pirate switched to the other side, fingers pinching the abused nipple and scratching over with a nail. Dipper chuckled against him, laving his tongue over the new hardened nub, and rolled it with his teeth.

“You sound like you’re having a lot of fun there, sweetheart,” Dipper hummed against him. Bill chomped down on his bottom lip to muffle his moans, voice going high in protest.

“Jus--Just fuck me already,” he whined, fin flicking restlessly. “You’re fucking  _ infuriating. _ ”

“Not with that attitude, I’m not.” Dipper snorted and let up, the red color of his lips matching Bill’s nipples from the suction. “I get my boyfriend back just to be told I’m infuriating? No, I don’t think I will. Not yet.”

Bill clenched his jaw, the need bubbling in his chest that bordered on crying shifting over into something angry. “Are you  _ fucking _ kidding me? Getting me all worked up, making me say those things, to get nothing?”

“Sounds like someone’s being a bit of a brat,” Dipper tsked in reply. He took it all in stride-- he knew Bill wasn’t truly mad at him, because he usually threw little fits like these. There was a reason why Dipper prided himself in being a brat tamer. “Before you bad mouthed me, I was considering on fucking you in the next minute, actually.” He watched Bill pale, smirking. “Didn’t think of that, now, did you?”

Oh, that was a sure way to break Bill down. His mouth opened and closed like a fish gasping for air, trying to find intelligent words to spit at Dipper, only to fail. “P-Please,” he whispered.

Dipper blinked. “What was that?” He raised a brow, turning his head so his ear was closer to Bill. “Sorry, I could have sworn you said please.”

Bill ground his teeth down, flushing a bright angry red. Jesus, Dipper truly  _ was _ infuriating. He wanted nothing more than to shove him down and teach the bastard a lesson, but they both knew that Bill would crumble and become a pillow princess once again. “Please,” he repeated a little bit louder.

Dipper’s features screwed up in feigned confusion, leaning closer. “Sorry, one more ti--”

“ _ Please! _ ” Bill snapped. “Please, I said fucking  _ please! _ ”

Dipper’s lips pulled into a knowing grin and he looked Bill in the eyes. He knew he won this battle, and he would win the war too. “The one and only Bill Cipher, strongest siren in all the seven seas, saying  _ please _ ? Wow, it must be Christmas!”

“Stop teasing me and just get on with it,” Bill whined. He outstretched his hands and grabbed at Dipper’s sides, pulling him down. Instead of resisting, Dipper laughed loudly and let himself be moved. He already won anyway.

“Ah, whiny as ever,” he teased. “But now that you’ve said please, I’m a little more open to negotiation. See what being nice gets you?” Dipper ducked his head and pressed his lips to Bill’s neck, right above his gills, and sucked. He slipped a hand between them and rubbed BIll’s slit, fingers almost dipping down inside with each stroke. The water was lubrication enough to rub with no discomfort.

Bill moaned, arching up into Dipper’s touch and tilting his head away. He loved it so damn much whenever Dipper necked him like this, marked him as his own. But mostly he was focusing on the taunting fingers so close to breaching him that he ached.

Dipper took great satisfaction in listening to all of Bill’s cute little noises. He’d waited for so long and  _ had _ said please, so he supposed he should give Bill more of a reward. Dipper finally pressed his fingers inside of Bill.

Bill’s mouth opened in a gasp, eyes rolling back. Oh,  _ jesus, _ he had needed this so damn bad. His pussy clenched tight around Dipper’s fingers greedily, trying to keep them inside and fill him up. The itch that had nagged at him for months was finally scratched, sated by his partner.

Dipper licked a stripe up Bill’s flaring gills with a light, ticklish tongue. Over the time of getting to know Bill, he’d discovered that his gills were very sensitive, but couldn’t be messed with much or his breathing would be impacted. Instead, Dipper would pay attention to the skin surrounding them. “Oh, you’ve really wanted me, haven’t you?” he rumbled in Bill’s ear, curling his fingers. Below him, Bill stiffened and bit off a keen.

“F--Fuck yes, oh fuck yes, I need you,” Bill moaned out. His sharp claws, perfect for tearing prey apart, dug into Dipper’s sides. His hips bucked and ground up into Dipper’s hand desperately.

“Just wait a little bit longer and I’ll fuck you nice and deep.” Dipper wanted to crumble Bill even more, cover his skin in hickies and stretch out this hot, wet pussy of his. He listened to Bill’s high whimper and the restless flapping of his fin, but continued on at his own pace.

One after another, Dipper kissed, sucked,  _ bit _ dark bruises into the vast expanse of Bill’s tanned neck and chest. His tongue pressed into the hollow of Bill’s throat hotly and he felt the siren shiver beneath him.

“Please, please, please,” Bill whispered, over and over again like a mantra. He’d waited, he’d complained and even pleaded-- he’d done every way in the book to get something out of Dipper and now he was stuck, floating away in aimless pleasure with no destination.

Each please was one step closer to making Dipper snap, desire building up and threatening to overpower self control. He’d been able to cover his boyfriend in enough hickies to last him at least a week, and now that he was satisfied, he let himself give in.

“You want my dick so bad?” Dipper sat back up and grasped his cock, the tight stroke up bringing dribbling precum from the tip. He watched Bill nod frantically, how his cheeks darkened even more. Oh, he was so beautiful-- darkly tanned skin marked up in bites and bruises, hot and needy. “You want this so deep inside I mess up your insides?”

“Fuck yes,” Bill moaned, pressing his hips up in hopes of luring Dipper back in. “Cripple me, Pinetree, fuck me so hard you knock me up.” He’d produced a batch of eggs a few times, almost always occurring after long, rough nights of passionate sex. Nothing ever hatched from them, but it was still testament to how hard they went.

God, how could Dipper ever say no to that? Something about filling Bill up so deep, then watching him pump out dozens of eggs just to be fucked again… It made something in him purr in deep satisfaction.

Dipper lunged forward and kissed Bill so hard that their teeth clacked together, lining his dick up with Bill’s slit. He brushed the head along the slit and it quivered, Bill’s high whine coming through the tongue-filled kiss. Finally he pushed inside.

Both of them moaned into each other’s mouths, panting and licking like animals. Bill’s pussy was so hot and tight around Dipper’s cock, driving him up the wall. Bill finally felt a sense of relief with being filled up, his Pinetree’s girth stretching him out wide.

Their bodies writhed and wet skinned rubbed together, the water splashing around in the tub with their near frantic movements. Dipper snapped his hips in a quick, sharp rhythm, sending him deep inside Bill’s pussy with each thrust. To the same rhythm, Bill’s tail twitched, causing the water to spill onto the wood floor.

Fucking  _ hell _ , Bill had so needed this. God. He wanted Dipper’s cock so damn bad and now he was getting it, unable to  _ think _ , sounding like a bitch in heat. Dipper’s sinful mouth on his muffled the louder ones from drifting beneath the door into the other rooms. He wrapped his arms around Dipper’s torso and dug his nails in, scratching his poor back up to bits. “F-- Ohhohoh yesssyesyeys-- faster ohffuckmeeeee--” he sobbed.

The great Bill Cipher was in complete shambles from some teasing and Dipper was  _ living _ for it.  _ He _ did this to him.  _ He _ brought the predator down into a pleading, sobbing mess.  _ He _ was the only one who would ever hear such filthy, gorgeous sounds coming from such an untouchable creature. Every little bit of squirming, pleading, horny siren beneath him was all thanks to Dipper fucking Pines. Pride burned in Dipper’s chest, filling him with fuel as their hips slapped together in wet, squelching slaps.

Bill babbled between deep, spitty kisses, eyes rolled back. He didn’t know what he wanted anymore, much less what he was saying, but the one thing he needed was for Dipper to continue. He needed to cum, needed to squeeze tight around Dipper and be filled with all that delicious, warm, white cum. Bill wanted it to flood in insides and replace the very blood that ran through his veins.

Dipper’s poor back was scratched up to pieces by now, but he couldn’t care-- being a masochist had its benefits, especially when your boyfriend was a predator who tore live things open for dinner. ( _ Oh, how Dipper ached for Bill to use those claws, pick out his insides… _ )

“You feel so good,” Dipper groaned, dropping his head down to Bill’s shoulder. All his focus and energy was put into fucking Bill the fastest, hardest way possible. Judging by the prostitute-like sounds coming from that beautiful throat, it was working. “I’d do this all day, watch you squirm beneath me, stuff you full…”

The fact that Dipper wanted Bill just as much as Bill needed him made the siren even more horny. Bill never wanted this to end, to forever be Dipper’s little fuck toy and spend his days in eternal orgasm.

“F--Fuck,” Bill choked out, squeezing his eyes shut tight, “I’m g’nna cum--” The pressure in his abdomen that told him he was about to orgasm was building quickly, so slow yet so quick at the same time. “Don’t stop, I’m gonna cum--”

“Like I’d ever stop.” Dipper lifted his head, a drop of sweat running down the back of his neck. His own end was fast approaching too, but he’d be damned if he missed Bill’s expressions.

Bill’s gradually tensed the closer he got, his words slurring and rising in volume the closer he got. “H-Harder-- g’nna cum g’nnac’m,  _ I’m cumming--! _ ” His body seized, eyes squeezed shut and jaw dropped as an overwhelming wave of pure, white hot pleasure overtook his body. His nails dug into Dipper’s skin like a vice, holding on for grounding, while his fin twitched sporadically.

Dipper saw fucking stars, Bill’s pussy clenching and convulsing around him in quick, throbbing rhythms that tipped him over the edge immediately. His own orgasm hit him and he groaned, the knot in his abdomen unwinding quick. His cock pumped thick, warm cum in spurting ribbons into Bill.

They both quivered, breath coming in sharp, shaky gasps. Sweat and water mixed on their skin, similar pangs of bliss relaxing their muscles. The high was always so sweet.

Slowly, Dipper and Bill opened their eyes. Dark, comforting brown met piercing gold, their pupils blown wide and lids drooping. They were both exhausted and worn out now, but neither of them regretted a thing.

Wordlessly, Dipper leaned down and just barely brushed his lips against Bill’s. They shared a tender kiss that made both of their hearts flutter.

“I love you,” he whispered.

“I love you too, Pinetree,” Bill whispered back.

Dipper got them both cleaned up once he was out of the tank and supplied Bill some fresh water until they could change the tank out tomorrow. Bill had nearly depleted the oxygen from his current change from their round, but the extra bucket-fulls should tie him over until then.

As he stroked Bill’s cheek with a gentle hand while his siren drifted off to sleep, tail curled up and body relaxed, Dipper thought to himself. He thought about their relationship, about their love, their individual and shared goals. He thought about the treasure, the time away, how happy Bill always looked when he saw him.

Dipper looked down to Bill’s sweet, peaceful sleeping face and smiled.

“Y’know,” he murmured softly. “I’m starting to think you’ve been my real treasure all along.”

**Author's Note:**

> This is a birthday fic for my RP partner, the one and only dorky_dipper! God, I've been sitting on this fucker for an entire month, chipping away at it little by little every night. It's really late, but it's done, and it's tasty. And I'm so, very tired.
> 
> Considering it's now October 1 and day 1 of Kinktober is 'teasing,' I'm labeling this as a duel 'birthday' and 'kinktober' oneshot because it fits.
> 
> Thank you so much for reading! Please let me know what you thought in the comments. Consider checking me out on tumblr too! (mindscapewish-writes)


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